In recent years, stereoscopic image display art that uses binocular disparity has attracted attention. Humans perceive three dimensions by differences in left-eye and right-eye retinal images. In the above recited art images exhibiting a disparity (a left-view image and a right-view image) are isolated and focused into the left and right eyes of a viewer respectively creating a disparity between an object image formed on the retina of the left eye and an object image formed on the retina of the right eye, which gives a perception of depth. Devices capable of taking stereoscopic photographs are expected to further increase in number, these devices not being limited only to digital cameras, but also including other devices such as smart phones.
With the increasing spread of the stereoscopic image display art one challenge is to provide users with a new experience of processing stereoscopic images in addition to the traditional experiences of capturing and viewing stereoscopic images. For example Patent Literature 1 discloses an art for arranging graphics such as speech bubbles or letters on a stereoscopic image, captured by a camera or other device, and creating a composite image. More specifically, the art disclosed in Patent Literature 1 achieves a stereoscopic effect by determining relative sizes and depths of a plurality of graphics in accordance with depth information (a depth map) for the stereoscopic image at an arrangement position of each of the graphics.